Hardware components

Story

Today I introduce to you the Force Sensing Resistor FSR 402 from Interlink Electronics. This flexible bendable and very narrow touch sensor can be controlled without Libary with any device.

FSR 402

a giant drag to just 62 mm

The 2 pictures show front and back:

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1 / 2 • front

A wooden toothpick is already quite thick against the paper thin sensor:

thin sensor - view by side

My setup shows the interaction with a Particle Photon and shows how sensitive the Tourchfeld reacts. Upon touching the sensitive field, the D7 LED of the photon is turned on and turned off as soon as the contact is released.

schematic

Schematic

The sensor does not have 3 inputs, just 2, so I chose the setup: one of the cables (black) on GND of the photon and the other cable (red) on D4 of the photon. Which contact you activate with the sensor is not relevant.

Fields of application of the sensor

The FSR 402 model is a single-zone Force Sensing Resistor® optimized for use in human touch control of electronic devices such as automotive electronics, medical systems, and in industrial and robotics applications. FSRs are two-wire devices. They are robust polymer thick film (PTF) sensors that exhibit a decrease in resistance with increase in force applied to the surface of the sensor. It has a 14.7mm diameter active area and is available in 4 connection options. Interlink Electronics FSR 400 series is part of the single zone Force Sensing Resistor family. Here the link to the manufacture.

Tutorial

Alternative

Code

FSR 402 - put the LED on/off

C/C++

// Touch-Sensor Particle Photon - works with v0.7.0 without Libaries// Ingo Lohs, v1.0 v. 08.04.2018// after the touch of the sensor, the Photon LED is on// DefinitionsconstintTOUCH_PIN_IN=D4;// Pin connected to SIG at Touch-SensorconstintLED_PIN=D7;// LED pinunsignedlonglastmillis=0;// time for interation the loopvoidsetup(){pinMode(TOUCH_PIN_IN,INPUT);pinMode(LED_PIN,OUTPUT);}voidloop(){if((millis()-lastmillis)>10){// play with the millislastmillis=millis();readData();}}voidreadData(){intproximity=digitalRead(TOUCH_PIN_IN);// Read the state of the sensorif(proximity==HIGH){digitalWrite(LED_PIN,LOW);// Turn the LED off}else{digitalWrite(LED_PIN,HIGH);// Turn the LED on}}